Arc regulator for calutron ion source



May 15, 1956 R. DE .LIBAN ARC REGULATOR FOR CALUTRON ION SOURCE 2 Sheets-Sheet 1 Filed May 3, 1946 INVENTOR. ROBERT De L/BA/V LW www ATTORNEY.

May 15, 1956 R. DE LIBAN 2,745,964

ARS REGULATOR FOR CALUTRON ION SOURCE:

Filed May 3, 194 2 Sheets-Sheet 2 INVENTOR. ofme L/BA/v BY z TTOR NEY.

ntec States Patent ARC REGULATOR FoR CALUTRoN N SOURCE Robert De Liban, Berkeley, Calif., assignor to the United States of America as represented by the United States Atomic Energy Commission Application May 3, 1946, Serial No. 666,909

11 Claims. (Cl. Z50-41.9)

The present invention relates to regulators for electric discharge devices and more particularly to regulators for calutron ion sources.

It is an object of this invention to provide an improved regulator for stabilizing the operation of a calutron ion generator.

Another object of this invention is to provide an improved regulator for stabilizing the operation of a calutron ion generator of the arc discharge type employing7 a filamentary cathode.

Still another object of this invention is to provide an improved regulator for a calutron ion generator of the type employing a lamentary cathode energized by alternating current.

Still another object of this invention is to provide an improved regulator for a calutron ion generator of the arc discharge type employing a lamentary cathode, including means for automatically protecting the lamentary cathode from electrical abuse.

At the outset, it is noted that a calutron is a machine of the character of that disclosed in the copending application of Ernest O. Lawrence, Serial No. 557,784, tiled October 9, 1944, and now Patent No. 2,709,222 granted May 24, 1955, and is employed to separate the constituent isotopes of an element and, more particularly, to increase the proportion of a selected isotope in an element containing several isotopes in order to produce the element enriched with the selected isotope. For example, the machine is especially useful in producing uranium enriched with U235.

Such a calutron essentially comprises means for vaporizing a quantity of material containing an element that is to be enriched with a selected one of its several isotopes; means for subjecting the vapor to ionization, whereby at least a portion of the vapor is ionized causing ions of the several isotopes of the element to be produced; electical means for segregating the ions from the un-ionized vapor and for accelerating the segregated ions to relatively high velocities; electromagnetic means for dellecting the ions along curved paths, the radii of curvature of the paths of the ions being proportional to the square roots of the masses of the ions, whereby the ions are concentrated in accordance with their masses; and means for de-ionzing and collecting the ions of the selected isotope thus concentrated, thereby to produce a deposit ol the element enriched with the selected isotope.

The invention, both as to its organization and method of operation together with other objects and advantages thereof, will be best understood by reference to the following specication taken in connection with the accompanying drawings in which:

Figure l is a diagrammatic plan view of a calutron and associated supply circuit together with the improved ion generator regulator;

Fig, 2 is a diagrammatic sectional view of the calutron taken along the line 2 2 of Fig. l;

Patented May 15, .1956

Fig. 3 is a schematic wiring diagram of the ion generator regulator shown in block form in Fig. l;

Fig. 4 is a voltage vector diagram employed for purposes of facilitating the explanation of the operation of Fig. 3; and

Fig. 5 is an auxiliary diagram showing the relationship of certain voltages and currents involved in the operation of the regulator of Fig. 3.

Referring now more particularly to Figs. l and 2 of the drawings, there is illustrated a representative example of a calutron 10 of the charactery noted, that comprises magnetic field structure including upper and lower pole pieces 11 and 12, provided with substantially tlat parallel spaced-apart pole faces and a tank 13 disposed between the pole faces of the pole pieces 11 and 12. The pole pieces 11 and 12 carry windings, not shown, which are adapted to be energized in order to produce a substantially uniform and relatively strong magnetic field therebetween, which magnetic field passes through the tank 13 and the various parts housed therein. The tank 13 is of tubular configuration, being substantially crescentshaped in plan, and comprising substantially at parallel spaced-apart top and bottom walls 14 and 15, upstanding curved inner and outer side walls 16 and 17, and end walls 18 and 19. The end walls 18 and 19 close the opposite ends of the tubular tank 13 and are adapted to be removably secured in place, whereby the tank 13 is hermetically sealed. Also, vacuum pumping apparatus, not shown, is associated with the tank 13, whereby the interior of the tank 13 may be evacuated to a pressure of the order of 10*5 to 10*4 mm. Hg. Preferably, the component parts of the tank 13 are formed of steel, the top and bottom walls 14 and l15 thereof being spaced a short distance from the pole faces of the upper and lower pole pieces 11 and 12, respectively, the tank 13 being retained in such position in any suitable manner, whereby the top and bottom walls 14 and 1S constitute in eiect pole pieces with respect to the interior of the tank 13, as explained more fully hereinafter. i

The removable end wall 18 suitably supports a source unit 20 comprising a charge receptacle 21 and a communicating arc block 22. An electric heater 54 is arranged in heat exchange relation with the charge receptacle 21 and is adapted to be connected to a suitable source of heater supply 51, whereby the charge receptacle 21 may be appropriately heated, the charge receptacle 21 being formed of steel or the like. Similarly, an arc block heater 53, connected to an arc block heater supply 50, is arranged in a heat exchange relation with the arc block 22. The arc block 22 is formed, at least partially, of carbon or graphite and is substantially C-shaped in plan, an upstanding slot 24 being formed in the wall there of remote from the charge receptacle 21. Thus, the arc block 22 is of hollow construction, the cavity therein communicating with the interior of the charge receptacle 21.

Also, the removable end wall 18 carries a tilamentary cathode 25 adapted to be connected to a suitable source of lament supply 52, the ilamentary cathode 25 overhanging the upper end of the arc block 22 and arranged in alignment with respect to the upperend of the cavity formed therein. The arc block 22 Acarries Van anode 26 disposed adjacent the lower end thereof and arranged in alignment with respect to the cavity formed therein. The lamentary cathode 25 and the cooperating anode 26 are adapted to be connected to a suitable source of are supply 55.

Further, the removable end wall 1S carries ion accelerating structure 39 formed of carbon or graphite and disposed in spaced-apart relation with respect to the Wall of the arc block 2.2 in which the slot 24 is formed. More specifically, a slit 40 is formed in the ion accelerating structure 39 and varranged in substantial alignment Vwith respect to the slot 24 formed in the wall of the arc block 22. A suitable source of accelerating electrode supply 57 is adapted to be connected with its positive terminal to the calutron ground and with its negative terminal t the ion accelerating structure 39. A suitable source of decelerating potential 56 is adapted to be connected with its positive terminal to the positive terminal of the are current supply 5S and .its negative terminal grounded.

The removable end wall 19 suitably supports a collector block 29 formed of stainless steel or the like and provided with two laterally spaced-apart cavities or pockets and 31 which respectively communicate with aligned slotsr32 and 33 formed in the wall of the collector block y 29 disposed remote from the removable end wall 19. lt

is noted that the pockets 30 and 31 are adapted to receive two constituent isotopes of an element which have been separated in the calutron 10, as explained more fully hereinafter. Further, the inner Wall 16 suitably supports a tubular liner 34 formed of copper or the like, rectangular in vertical cross-section, disposed within the tank 13 and spaced from the walls 14, 15, 16 and 17. One end of the tubular liner 34 terminates adjacent the accelerating structure 39; and the other end of the tubular liner 34 terminates adjacent the collector block 29; the tubular liner 34 constituting an electrostatic shield for the high velocity ions traversing the curved paths between the slit formed in the ion accelerating structure 39 and the slots 32 and 33 formed in the collector block 29. Finally, the tubular liner 34 is electrically grounded to the calutron ground. Thus, it will be understood that the source unit 2i) is connected to the positive terminal of Ithe arc current supply and of the decelerating potential supply 56, and the tank 13 and liner 34 are connected to the positive grounded terminal of the accelerating electrode supply and to the negative grounded terminal of the decelerating supply; while the ion accelerating structure 39 is connected to the ungrounded negative terminal of the accelerating electrode supply 57, the ion accelerating structure 39 and the collector block 29 being electrically insulated from the component parts of the tank 13.

Considering now the general principle of V'operation of the calutron 10, a charge comprising a compound of the element to be treated is placed in thecharge receptacle 21, the compound of the element mentioned being one whichfmay be readily vaporized. The vend walls 18 and 19 are securely attached to the open ends of the tank 13, whereby the tank 13 is hermetically sealed. The various electrical connections are completed and operation of the vacuum pumping apparatus, not shown, associated with the tank 13 is initiated. When a pressure of the order of 10-5 to 1.04 mm. Hg is established within the tank 13, the electric circuits for the windings, not shown, associated with the pole pieces 11 and 12 are closed and adjusted, whereby a predetermined magnetic tield is established therebetween traversing the tank 13. The electric circuits between the arc block heater 53 and the supply 50 and the charge receptacle heater 54 and supply 51 are closed, whereby the charge in the charge yreceptacle 21 is heated and vaporized yand the arc block brought upto operating temperature. The vapor tills the charge receptacle 21 and is conducted into the communicating cavity formed in the arc block 22. The electric circuit for the lamentary cathode 25 is closed, whereby the larnentary cathode is heated and rendered electron emissive. Then the electric circuit between the filamentary cathode 25 and the anode 26 is closed, whereby an arc discharge is struck therebetween, electrons proceeding from the filamentary cathode 2'5 to the anode 26. The stream of electrons proceeds into the arc block '22 and breaks 'up the molecular form of the compound uof the. vapor to a considerable extent, producing positive ions of the element 'that is to be enriched with the `selected one Y of its isotopes.

The electric circuit between the arc block 22 and the ion accelerating structure 39 is completed, the ion accelerating structure 39 being at a high negative potential with respect to the arc block 22, whereby the positive ions izi the arc block 22 are attracted by the ion accelerating structure 39 and accelerated through the voltage irnpressed therebetween. More particularly, the positive ions proceed from the cavity formed in the arc block 22 through the slot 24 formed in the wall thereof, and across the space between the ion accelerating structure 39 and the adjacent wall of the arc block 22, and thence 'through the slit 40 formed in the ion accelerating structure 39 into the interior of the tubular liner 34. However, in passing into the liner 34 the postive ions suffer a slight deceleration since the liner 34 is at a positive potential with respect to the accelerator 39. The high-velocity positive ions form a vertical upstanding ribbon or beam proceeding from the cavity formed in the arc block 22 through the slot 24 and the aligned slit 4t) into the tubular liner 34.

As previously noted, the collector block 29 and the tubular liner 34 are electrically connected and grounded whereby there is an electric-lield-free path for the highvelocity positive ions disposed between the ion accelerating structure 39 and the collector block 29 within the tubular liner 34. The high-velocity positive ions entering the adjacent end of the liner 34 are deected from their normal straight-line path and from a vertical plane passing through the slot 24 and the aligned slit 40, due to the elfect of the relatively strong magnetic lield maintained through the space within the tank 13 and the liner 34 through which the positive ions travel, whereby the positive ions describe arcs, the radii of which are proportional to the square roots of the masses of the ions and consequently of the isotopes of the element mentioned. Thus, ions of the relatively light isotope of the element describe an interior arc of relatively short radius and are focused through the slot 32 into the pocket 30 formed in the collector block 29; whereas ions of the relatively heavy isotope of the element describe an exterior are of relatively long radius and are focused through the slot 33 into the pocket 31 formed in the collector block 29. Accordingly, the relatively light ions are collected in the pocket 39 and are de-ionized to produce a deposit of the relatively light isotope of the element therein; while the relatively heavy ions are collected in the pocket 31 and are de-ionized to produce a deposit of the relatively heavy isotope of the element therein.

After all of the charge in the charge receptacle 21 has been vaporized, all of the electric circuits are interrupted and the end Wall 1S is removed so that another charge may be placed in the charge receptacle 21 and subsequently vaporized in the manner explained above. After a suitable number of charges have been vaporized in order to obtain appropriate deposits of the isotopes of the element in the pockets 30 and 31 of the collector block 29, the end wall 19 may be removed and the deposits 4of the collected isotopes in the pockets 30 and 31 in the collector block 29 may be reclaimed.

Of course, it will be understood that the various dimensions of the parts of the calutron 1t), the various elec trical potentials applied between the various electrical parts thereof, as well as the strength of the magnetic field between the pole lpieces 11 and 12, are suitably correlated with respect to each other, depending upon the mass numbers of the several isotopes of the element which is to be treated therein. In this connection, reference is again made to the copending application of Ernest O. Lawrence, for a complete specification of a calutron especially designed for the production of uranium enriched with the isotope U235. By way of illust-ration, it is noted that when the calutron 10 is employed in order to produce uranium enriched with Um, the compound of uranium which is suggested as a suitable charge in the charge receptacle 21 is UClt, as this compound may be readily vaporized and the molecular form of the vapor may be readily broken up to form positive ions of uranium with great facility. ln this case, uranium enriched with U235 is collected in the pocket 30 of the collector block 29, and uranium comprising principally U238 is collected in the pocket 31 of the collector block 29. Also, it is noted that from a practical standpoint, the deposit of uranium collected in the pocket 30 of the collector block 29 contains considerable amounts of U238, in view of the fact that this isotope comprises the dominant constituent of normal uranium. Furthermore, the deposit of uranium collected in the pocket 30 of the collector block 29 contains a considerably increased amount of U234, in view of the fact that it is not ordinarily feasible to separate U2 and U235 in the production of relatively large quantities of uranium enriched with U235 for commercial purposes. Accordingly, in this example the uranium deposited in the pocket 30 of the collector block 29 is considerably enriched, both With U234 and with U235, and considerably impoverished with respect to U238 as compared to natural or normal uranium.

In the operation of the calutron 10, it is highly desirable that a relatively intense stable beam of positive ions be projected by the ion accelerating structure 39, through the liner 34, toward the collector block 29; which operating condition requires that the source unit 20 be productive of a steady and copious supply of positive ions. To accomplish this end in the source unit 20, the arc discharge through the cavity in the arc block 22 must be both relatively intense and uniform. Moreover, it is desirable that such an arc discharge should be steady and free from both intensity and position variations in order that the ion source unit 20 be productive of a highly continuous, copious and uniform supply of positive ions. Furthermore, the ion source unit 20 should be so constructed and arranged that the parts thereof are subjected to minimum wear and erosion, whereby the unit has a long life and an ecient operating characteristic.

Having described the structural features of the calutron and the general operation thereof, the electrical circuit connections between the various electrodes and elements of the ion generator and regulator and the various sources of supply will now be described. Sources of current supply 50, 51, and 52 which are energized from different phases of the same polyphase power circuit are connected to the arc block heater 53 to the charge receptacle heater 54 and the ion generator filament 25, respectively, as was hereinbefore briey pointed out. One side of the filament 25 is also connected to the negative terminal of the arc supply 55 and the positive terminal of this arc supply is connected to the positive terminal of the decelerator voltage supply 56 and to the anode 26 of the ion generator 20 as Well as to the arc block 22 thereof. The negative terminal of the decelerator voltage supply is grounded as is the liner 34 of the calutron. The positive terminal of the accelerator voltage supply 57 is also grounded and the negative terminal of this supply is connected to the accelerator structure 39 which is positioned between the ion generator 20 and the liner 34 in such manner that the slots thereof are substantially in alignment. Terminals I, E, and M of the regulator 58, which controls the heating current to the ion generator filament 25 in accordance with the arc current, are connected to be supplied with signal currents from three current transformers 59, 69, and 61 associated with the input power feeders of the arc current supply 55 so that this regulator may function to regulate through terminals XB the current fed to the filament power supply 52. The terminals OR of the regulator 58 are connected across a phase of the supply voltage feeding the arc supply 55 for the purpose of closing the relay 91 in Fig. 3 when input voltage is connected to the arc supply 55, as will be hereinafter more fully described. The secondaries of the current transformers 59, 60, and 61 are shunted by resistors 63, 64, and 65, respectively, for the purpose of providing a permanent load on the secondaries.

The circuit arrangement of the regulator 58 is schematically set forth in Fig. 3 and reference is now made to this iigure in detail.

The three-phase A. C. signal obtained from the secondaries of the current transformers, and appearing across terminals I, E, and M, is ampliied by transformers 66, 67, and 68, which are connected in delta-Wye for maximum voltage step-up, and is then rectified by a conventional three-phase full wave rectifier consisting of tubes 69, 70, and 71. The resulting D. C. signal is filtered by an L-type filter comprising the inductance 74 and capacitors 72 and 73, the filter being designed with maximum attenuation at the principal ripple frequency whereby adequate filtering is obtained without the addition of a long time delay to the regulating loop. Also, potentiometer 75 which terminates the filter is chosen for optimum transient response. A portion of the rectier output voltage is selected by the variable contactor of potentiometer 75, which serves as the arc current control, and is compared with a standard battery 77, the difference signal being applied between the cathodes and control grids of thyratron tubes 89 and 90 through a grid phasing network, which supplies pre-phased A. C. signals that are superimposed upon the D. C. signal. This general system of thyratron control, using a combined D. C. and A. C. voltage, is well known to the art and will not be further explained here. However, the phasing network comprising resistors 8G, 81, 82, 83, and 86 and the capacitors 84 and 8S will be further considered in connection with Fig. 4.

In this ligure, the voltage vector AC represents the secondary voltage of transformer 79 in Fig. 3, the primary of which is connected to a single phase A. C. supply line. This transformer furnishes the filament voltage for the various regulator tubes in addition to supplying the phasing network. Point H represents the potential at the mid-tap of the secondary winding of transformer 79 and is electrically neutral with respect to the A. C. potential developed therein. Vector D] represents the voltage across the gain-control resistor 82, this resistor being the variable portion of a voltage divider comprising resistors 80, S1, and 82. The series networks, consisting of resistor 83 and capacitor 84, and resistor 86 and capacitor 85, are shunted across resistor 82 but, because of their high impedance compared to resistor 82, have little eifect upon the phase of the voltage appearing across resistor 82. Thus, vector DI is shown in phase with vector AC. Also, as the length of vector DI is varied by adjusting resistor 82, the radius of the circumscribed circle and the magnitude of the vectors therein likewise vary in proportion, since they are derived from vector DJ. Point H remains xed, however, because of the equality of vectors AD and JC which represent respectively the voltages across the equal resistors 81 and 80. The vectors HG and HF represent the A. C. voltages applied to the grids of tubes 89 and 90, and may be adjusted in phase without appreciably changing their magnitude by varying resistors 83 and 86. Normally these resistors are adjusted to equal the impedance of the capacitors 84 and 85, which are also equal to each other, so that the resulting grid voltages are lagging the corresponding anode voltages by approximately and are phased with respect to one another.

Resistors 87 and 8S limit to a small value the grid current drawn by tubes S9 and 90 during each half cycle. Transformer 96, the primary of which is connected to the same single phase supply line that feeds transformer 79, furnishes anode voltages of the proper phase to tubes 89 and 90, these tubes functioning as a grid controlled full wave rectier. The rectified output current ows through the parallel combination of resistors 93 and 95 and through the D. C. control winding of a saturable reactor 97, the A. C. windings of which are connected in ser-ieswith the power line feeding the source unit filament supply via terminals X and B. Since the resistance of potentiometer 95 is high .compared to that of resistor 93 and since the contact of relay 91 is normally closed in operation, the magnitude of the current owing through the D. C. control winding of the saturable reactor 97 is mainly determined by the setting of the variable contactor 94 of resistor 93. This is adjusted initially to suit the requirements of a given reactor 97.

In operation, the above-described regulating loop functions as follows: An increase in arc current causes an increase in the A. C. signal obtained from current transformers 59, 60, and 61 and this in turn causes an increase in the D. C. output voltage of the three-phase full wave rectifier, whereby a more negative potential is impressed upon the control grids of tubes $9 and 90. This increased D. C. potential, in conjunction with the superimposed A. C. grid signals, reduces the tiring angle of tubes 89 and 9i) and hence the magnitude of the average rectified control current therefrom. This reduced D. C. control current increases the reactance of reactor 97, resulting in a reduction of voltage supplied to the lamentary cathode 25. The consequent drop in emission from the iilamentary cathode opposes the original increase of arc current and thereby tends to stabilize the arc current about its original value, this value being adjustable by means of potentiometer 75.

In the use of this regulating system, if the filamentary cathode 25 were energized when the arc supply is ofi,

the regulator unit would tend to increase the current to the tilamentary cathode to a maximum limited only by the capacity of the filament supply and the saturation impedance of reactor 97. Since this might damage or burn out the iilamentary cathode 25, an auxiliary circuit consisting of relay 91 and the variable contact 92 of resistor 93 is used. Thus, if the arc supply is deenergized for any reason, the contacts of relay 91 open and an additional resistance is inserted in series with the D. C. control winding of the saturable reactor 97. This in turn reduces the maximum current that can be supplied to the lamentary cathode 25 to a safe value.

Another auxiliary circuit, consisting of resistor 76, diode 78, and the potentiometer 95, is also included in the regulator unit for the purpose of limiting to a predetermined value the maximum iilamentary cathode current obtainable under normal operating condition. This circuit is considered in connection with Fig. 5, in which for simplicity, straight line functions are assumed between the various quantities. Curve S represents the tilamentary cathode current In as a function of the D. C. grid voltage EG applied to the tubes 89 and 90. Curve T shows the relationship between the voltage En developed across that portion of potentiometer 95 between the sliding contact and ground and the filamentary cathode current IF. Thus, it will be seen that as the lamentary cathode current IF is increased, the D. C; grid voltage of tubes 89 and 90 increases in the positive direction with respect to ground, whereas En increases in the negative direction. Now, if it is assumed that the anode of diode 78 is connected to the furthermost positive tap on battery 77 and if it is also assumed that diode 78 conducts when its anode is posit1ve with respect to its cathode, it will be apparent that the intersection of curves S and T represents the point at which this conduction will start. if the arc current control potentiometer 75 is adjusted in an attempt to obtain a higher arc current than that corresponding to this intersection, tube 78 will conduct and the additional signal voltage will appear across resistor 76 without reaching the grid circuit, inasmuch as this resistor is a very high resistance compared to that of potentiometer 95 and tube 78. As a resultJ curve S will depart from its normal slope at this intersection point and describe a plateau at a value .indicated as In' on Fig. 5. This limiting value of lamentary cathode current can be adjusted by changing the position of the variable contact of potentiometer 95. ForV instance, an increased resistance -between this contact and ground would give a curve such as that shown as U in Fig. 5. The intersection of this curve with curve S would then give a lower limiting value of lamentary cathode current as indicated by In. An additional variable is available in the adjustable battery tap shown on Fig. 3. lf this is moved from the positive end of the battery to some intermediate point, another curve such as that indicated as curve V on Fig. 5 will be obtained which in turn produces a new intersection point and hence another limiting value of lilamentary cathode current. This variable limiting feature is use to accommodate the variations found in filamentary cathodes. Because of the sharpness of this control the limiting filament current can be set, once the arc has been initiated, to a value only slightly higher than the required running current without interfering with the normal regulating action.

ln the manner described in the foregoing specifica tion, the present invention provides for stabilization of the arc in the calutron ion generator, thereby insuring a copious and uniform supply of ions. It is noted also that Vthe present invention includes means for protecting the ilarnentary cathode of the ion generator from electrical abuse, whereby longer cathode life is obtained. Further, since the power lines feeding the arc supply and the lamentary cathode supply are near ground potential, and since the arc regulator is associated with the ion generator only by means of these lines, it is apparent that the present invention allows the operation of the arc regulator unit and its associated controls at ground potential regardless of the high potentials applied to the ion generator unit, provided of course that the arc supply and the lamentary cathode supply transformer have adequate interwinding insulation.

While there has been set forth herein a preferred embodiment of this invention, it is not desired to limit this invention to the exact details described except insofar as they may be set Vforth in the claims.

What is claimed is:

l. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc between said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. Winding, said A. C. Winding being connected between said source of alternating current and said cathode power supply, means responsive to the current supplied said arc current supply from said source of alternating current for obtaining an A. C. signal substantially proportional to the arc discharge current, and means responsive to said A. C. signal for supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode.

2. A calutron ion source regulator comprising in cornbination an ion source having a cathode and an anode, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc between said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected between said source of alternating current and said cathode power supply, current transformers connected in series with said source of alternating current and said arc power supply whereby an A. C. signal substantially proportional to the arc discharge current is obtained, and electronic means responsive to said A. C. signal supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained sub- 9 stantially constant through the control of the heating current to said cathode.

3. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, wall structure for defining an ionization chamber between said cathode and said anode, means for feeding material to be ionized into said ionization chamber, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc between said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. winding, said cource of alternating current being connected to said cathode power supply through said A. C. winding, current transformers responsive to the current supplied said arc current supply by said source of alternating current for obtaining an A. C. signal substantially proportional to the arc discharge current, and means responsive to said A. C. signal for supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode.

4. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, an alternating current power supply for heating said cathode to electron emissive temperature, a direct current power supply for supplying an arc between said cathode and said anode, a source of alternating current for energizing said alternating current power supply and said direct current power supply, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected between said source of alternating current and said alternating current power supply, current transformers connected between said source of alternating current and said direct current power supply whereby an A. C. signal substantially proportional to the arc discharge current is obtained, a pair of gas triodes connected to the D. C. winding of said saturable reactor, and a phasing network responsive to said A. C. signal for controlling the tiring angle of said gas triodes, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode.

5. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, wall structure for delining an ionizing chamber between said cathode and said anode, means for feeding material to be ionized into said ionization chamber, an alternating current power supply for heating said cathode to electron emissive temperature, a direct current power supply for supplying an arc between said cathode and said anode, a source of alternating current for energizing said alternating current power supply and said direct current power supply, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected between said source of alternating current and said alternating current power supply, current transformers connected between said source of alternating current and said direct current power supply for obtaining an A. C. signal substantially proportional to the arc discharge current, a signal rectitier for converting said A. C. signal to a D. C. signal, a pair of gas triodes connected to the D. C. winding of said saturable reactor, and a phasing network for combining said D. C. signal with pre-phased A. C. voltages to control the tiring angle of said gas triodes, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode.

6. A calutron ion source regulator comprising in comprising in combination an ion source having a cathode and an anode, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc between said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. winding, said A. C". winding teilig connected between said source of alternating current and said cathode power supply, means responsive to the current supplied said arc current supply by said source of alternating current for obtaining an A. C. signal substantially proportional to the arc discharge current, means responsive to said A. C. signal for supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic limiting circuit, including a unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value, and an electrical interlock circuit for reducing the current supplied to said cathode whenever said direct current supply is not energized.

7. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc between said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected between said source of alternating current and said cathode power supply, current transformers connected between said source of alternating current and said arc power supply whereby an A. C. signal substantially proportional to the arc discharge current is obtained, electronic means re sponsive to said A. C. signal for supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic hunting circuit, including a unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value, and an electrical interlock circuit for reducing the current supplied to said cathode whenever said direct current supply is not energized.

8. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, wall structure for defining an ionization chamber between said cathode and said anode, means for feeding material to be ionized into said ionization chamber, a cathode power supply for heating said cathode to electron emissive temperature, an arc power supply for maintaining an arc betweenk said anode and said cathode, a source of alternating current for energizing said power supplies, a saturable reactor having an A. C. and a D. C. winding, said source or' alternating current being connected to said cathode power supply through said A. C. winding, current transformers responsive to the current supplied said arc current supply by said source of alternating current for obtaining an A. C. signal substantially proportional to the arc discharge current, means resporp sive to said A. C. signal for supplying D. C. current to said D. C. winding of said saturable reactor, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic limiting circuit, including a unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value, and an electrical interlock circuit for reducing the current supplied to said cathode whenever said direct current supply is not energized.

9. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, an alternating current power supply for heating said cathode to electron emissive temperature, a direct current power supply for supplying an arc between said cathode and said anode, a source of alternating current for energizing said alternating current power supply and said direct current power supply, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected between said source of alternating current and said alternating current power supply, current transformf ers connected between said source of alternating current and said direct current power supply whereby an A. C. signal substantially proportional to the arc discharge current is obtained, a pair of gas triodes connected to the D. C. winding of said saturable reactor, a phasing network responsive to Said A. C. signal for controlling the firing angle of said gas triodes, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic limiting circuit, including unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value, and an electrical interlock. for reducing the current supplied to said cathode whenever said direct current supply is not energized.

10. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, wall. structure for defining an ionizing chamber between said cathode and said anode, means for feeding material to be ionized into said ionization chamber, an alternating current power supply for heating said cathode to electron emissive temperature, a direct current power supply for supplying an arc between said cathode and said anode, a source of alternating current for energizing said alternating current power supply and said direct current power supply, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected in series with said source of alternating current and said alternating current power supply, current transformers connected in series with said source of alternating current and said direct current power supply for obtaining an A. C. signal substantially proportional to the arc discharge current, a signal rectifier for converting said A. C. signal to a D. C. signal, a pair of gas triodes connected to the D. C. winding of said saturable reactor, a phasing network for combining said D. C. signal with pre-shaped A. C. voltages to control the firing angle of said gas triodes, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic limiting circuit, including a unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value, and an electrical interlock circuit for reducing the current supplied said cathode whenever said direct current supply is not energized.

11. A calutron ion source regulator comprising in combination an ion source having a cathode and an anode, wall structure for defining an ionizing chamber between said cathode and said anode, means for feeding material to be ionized into said ionization chamber, an alternating current power supply for heating said cathode to electron emissive temperature, a direct current power supply for supplying an arc between said cathode and said anode, a source of alternating current for energizing said alternating current power supply and said direct current power supply, a saturable reactor having an A. C. and a D. C. winding, said A. C. winding being connected in series with said source of alternating current and said alternatd ing current power supply, current transformers connected in series with said source of alternating current and said direct current power supply for obtaining an A. C. signal substantially proportional to the arc discharge current, a signal rectifier for converting said A. C. signal to a D. C. signal, a second source of alternating current, a pair of grid-controlled gas rectiers connected between said second source of alternating current and the D. C. winding of said saturable reactor for supplying direct current to said D. C. winding, a phasing network for cornbining said D. C. signal with pre-phased A. C. voltages to control the tiring angle of said grid-controlled gas rectiers, whereby said arc discharge current is maintained substantially constant through the control of the heating current to said cathode, an electronic limiting circuit, including a unidirectional conducting element, for limiting the current supplied to said cathode to a predetermined value by limiting the tiring angle of said grid-controlled gas rectiiers, and an electrical interlock circuit for reduring the current supplied to said cathode whenever the said direct current supply is not energized.

No references cited.

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1. A CALUTRON ION SOURCE REGULATOR COMPRISING IN COMBINATION AN ION SOURCE HAVING A CATHODE AND AN ANODE, A CATHODE POWER SUPPLY FOR HEATING SAID CATHODE TO ELECTRON EMISSIVE TEMPERATURE, AN ARC POWER SUPPLY FOR MAINTAINING AN ARC BETWEEN SAID ANODE AND SAID CATHODE, A SOURCE OF ALTERNATING CURRENT FOR ENERGIZING SAID POWER SUPPLIES, A SATURABLE REACTOR HAVING AN A. C. AND A D. C. WINDING, SAID A. C. WINDING BEING CONNECTED BETWEEN SAID SOURCE OF ALTERNATING CURRENT AND SAID CATHODE POWER SUPPLY, MEANS RESPONSIVE TO THE CURRENT SUPPLIED SAID ARC CURRENT SUPPLY FROM SAID SOURCE OF ALTERNATING CURRENT FOR OBTAINING AN A. C. SIGNAL SUBSTANTIALLY PROPORTIONAL TO THE ARC DISCHARGE CURRENT, AND MEANS RESPONSIVE TO SAID A. C. SIGNAL FOR SUPPLYING D. C. CURRENT TO SAID D. C. WINDING OF SAID SATURABLE REACTOR, WHEREBY SAID ARC DISCHARGE CURRENT IS MAINTAINED SUBSTANTIALLY CONSTANT THROUGH THE CONTROL OF THE HEATING CURRENT TO SAID CATHODE. 